Linear compressor

ABSTRACT

The present invention relates to a linear compressor. The linear compressor according to an aspect of the present invention includes a spring axially elastically supporting a driving assembly. The spring includes a spring body axially extending, a front spring link forming an end of the spring body by extending from a side of the spring body, and a rear spring link forming the other end of the spring body by extending from the other side of the spring body. Any one of the front spring link and the rear spring link is fixed to the driving assembly and the other one is fixed to a supporting assembly.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.16/514,496, filed on Jul. 17, 2019, which claims priority to KoreanPatent Application No. 10-2018-0082696, filed on Jul. 17, 2018. Thedisclosures of the prior applications are incorporated by reference intheir entirety.

FIELD

The present disclosure relates to a linear compressor.

BACKGROUND

In general, a compressor, which is a mechanical apparatus that increasesthe pressure of air, a refrigerant, or other various working gases bycompressing them using power from a power generator such as an electricmotor or a turbine, is generally used for appliances or throughoutindustry.

Compressors can be classified in a broad sense into a reciprocatingcompressor, a rotary compressor, and a scroll compressor.

As for the reciprocating compressor, a compression space into or fromwhich a working gas is suctioned or discharged is formed between apiston and a cylinder and the piston compresses the refrigerant byreciprocating straight in the cylinder.

As for the rotary compressor, a compression space into or from which aworking gas is suctioned or discharged is formed between a roller thateccentrically rotates and a cylinder and the roller compresses theworking gas by eccentrically rotating on the inner side of the cylinder.

As for the scroll compressor, a compression space into or from which aworking gas is suctioned or discharged is formed between an orbitingscroll and a fixed scroll and the orbiting scroll compresses arefrigerant by rotating on the fixed scroll.

Recently, a linear compressor that can improve compression efficiencywith a simple structure without a mechanical loss due to conversion ofmotions by having a piston directly connected to a driving motor thatgenerates a straight reciprocating motion has been developed as one ofthe reciprocating compressors.

The linear compressor suctions, compresses, and then discharges arefrigerant by reciprocating straight the piston in a cylinder using alinear motor in a sealed shell.

Further, the linear compressor may include a resonant spring for stablymoving an actuator including the piston. The resonant spring isunderstood as a component that reduces vibration and noise due tomovement of the actuator.

The applicant(s) has filed the following Prior Art Document 1 inconnection with a linear compressor with a resonant spring structure.

<Prior Art Document 1>

1. Publication No.: 10-2018-0053859 (Publication Date: May 24, 2018)

2. Title of Invention: Linear compressor

A plurality of resonant springs is disposed behind a piston in thelinear compressor of Prior Art Document 1. The resonant springs includea first resonant spring disposed between a supporter that supports thepiston and a stator cover that supports an outer stator and a secondresonant spring disposed between the supporter and a rear cover.

The linear compressor of Prior Art Document has the following problems.

In Prior Art Document, an actuator that reciprocates is supported by thesupporter between the first resonant spring and the second resonantspring. Any one of the first resonant spring and the second resonantspring is compressed when the actuator reciprocates, thereby supportingthe actuator. That is, the actuator is supported only by compressiveforce of the first resonant spring and the second resonant spring.

In short, (1) only the compressive sections of the springs can be usedin the structure of Prior Art Document 1. Accordingly, there is aproblem that a plurality of springs has to be used to support thereciprocating actuator.

(2) Further, since only the compressive sections of the springs areused, the force that is applied to one spring is relatively small.Accordingly, there is a problem that large stress is generated in thesprings.

(3) Further, since a plurality of springs is installed, relatively manyspaces are required to install the springs. Accordingly, there is aproblem that a shell in which the springs are installed is increased insize, the size of the compressor is increased, and the installationspace is limited.

SUMMARY

The present invention has been made in an effort to solve the problemsand an object of the present invention is to provide a linear compressorthat uses both of tensile force and compressive force of a spring byfixing both ends of the spring.

In particular, an object of the preset invention is to provide a linearcompressor that supports a driving assembly that reciprocates, using onespring by using both of tensile force and compressive force of thespring.

Another object of the present invention is to provide a linearcompressor including small and compact shell because one spring isdisposed in the shell.

A linear compressor according to an aspect of the present inventionincludes: a shell that forms an external shape; a driving assembly thataxially reciprocates in the shell; a supporting assembly that supportsthe driving assembly in the shell; and a spring coupled to the drivingassembly and the supporting assembly to axially elastically support thedriving assembly.

The spring includes a spring body axially extending, a front spring linkforming an end of the spring body by extending from a side of the springbody, and a rear spring link forming the other end of the spring body byextending from the other side of the spring body.

Any one of the front spring link and the rear spring link is fixed tothe driving assembly and the other one is fixed to a supportingassembly.

Accordingly, the spring is fixed at both ends and can elasticallysupport the driving assembly using both of tensile force and compressiveforce.

According to the linear compressor of an embodiment of the presentinvention having the configuration described above, there are thefollowing effects.

It is possible to support a driving assembly that reciprocates with onespring using both of tensile force and compressive force of the springwith both ends of the spring fixed.

In particular, since both of tensile force and compressive force of thespring are used, the spring can support larger load or repetitive load.

Further, since the driving assembly is supported by one spring, theinside of the shell in which the spring is installed can be simplified.Further, it is possible to reduce the size of the shell, whereby thesize of the linear compressor is decreased. Further, a space where thecompressor is installed can be reduced, so the compressor can be morefreely installed.

Further, the spring can be formed in various shapes. Accordingly, it ispossible to effectively support the driving assembly by forming thespring in various shapes, if necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view showing a linear compressor according to an embodimentof the present invention;

FIG. 2 is an exploded view showing the components in the linearcompressor according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along line A′-A′ of FIG. 1;

FIG. 4 is a view showing a coupling structure of the linear compressoraccording to an embodiment of the present invention;

FIGS. 5 and 6 are views showing a spring of a linear compressoraccording to a first embodiment of the present invention;

FIGS. 7 and 8 are views showing a spring of a linear compressoraccording to a second embodiment of the present invention;

FIG. 9 is a view showing a coupling structure of a linear compressoraccording to another embodiment of the present invention;

FIGS. 10 and 11 are views showing a spring of a linear compressoraccording to a third embodiment of the present invention; and

FIGS. 12 and 13 are views showing a spring of a linear compressoraccording to a fourth embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention are described indetail with reference to exemplary drawings. When components are givenreference numerals in the drawings, the same components are given thesame reference numerals even if they are shown in different drawings.Further, in the following description of embodiments of the presentinvention, when detailed description of well-known configurations orfunctions is determined as interfering with understanding of theembodiments of the present invention, they are not described in detail.

Further, terms ‘first’, ‘second’, ‘A’, ‘B’, ‘(a)’, and ‘(b)’ can be usedin the following description of the components of embodiments of thepresent invention. The terms are provided only for discriminatingcomponents from other components and, the essence, sequence, or order ofthe components are not limited by the terms. When a component isdescribed as being “connected”, “combined”, or “coupled” with anothercomponent, it should be understood that the component may be connectedor coupled to another component directly or with another componentinterposing therebetween.

FIG. 1 is a view showing a linear compressor according to an embodimentof the present invention.

As shown in FIG. 1, a linear compressor 10 according to an embodiment ofthe present invention includes a shell 101 and shell covers 102 and 103(see FIG. 3) combined with the shell 101. In a broad sense, the shellcovers 102 and 103 may be understood as components of the shell 101.

Legs 50 may be coupled to the bottom of the shell 101. The legs 50 maybe coupled to the base of a product on which the linear compressor 10 isinstalled. For example, the product may include a refrigerator and thebase may include the mechanical chamber base of the refrigerator.Alternatively, the product may include the outdoor unit of anair-conditioning system and the base may include the base of the outdoorunit.

The shell 101 may have a substantially cylindrical shape and may be laiddown laterally or axially. On the basis of FIG. 1, the shell 101 may belaterally elongated and may have a relatively small radial height. Thatis, the linear compressor 10 may be small in height, so when the linearcompressor 10 is disposed on the base of the mechanical chamber of arefrigerator, the height of the mechanical chamber can be reduced.

Further, the shell 101 of the linear compressor 10 according to anaspect of the present invention may have a relatively small laterallength. In this case, the length means an axial length. This is becausea supporting structure of a driving assembly to be described below issimplified. Accordingly, the shell 101 has a relatively small volume, soa space for installing the linear compressor 10 can be considerablyreduced.

A terminal 108 may be disposed on the outer side of the shell 101. Theterminal 108 is understood as a component that transmits external powerto a motor assembly 140 (see FIG. 3) of the linear compressor. Theterminal 108 can be connected to a lead wire of a coil 141 c (see FIG.3).

A bracket 109 is disposed outside the terminal 108. The bracket 109 mayinclude a plurality of brackets disposed around the terminal 108. Thebracket 109 may perform a function of protecting the terminal 108 fromexternal shock.

Both sides of the shell 101 are open. The shell covers 102 and 103 canbe coupled to both open sides of the shell 101. In detail, the shellcovers 102 and 103 include a first shell cover 102 coupled to one openside of the shell 101 and a second shell cover 103 coupled to the otheropen side of the shell 101. The internal space of the shell 101 can besealed by the shell covers 102 and 103.

In FIG. 1, the first shell cover 102 may be positioned at the right sideof the linear compressor 10 and the second shell cover 103 may bepositioned at the left side of the linear compressor 10. That is, thefirst and second shell covers 102 and 103 may be arranged opposite eachother.

The linear compressor 10 further includes a plurality of pipes 104, 105,and 106 disposed at the shell 101 or the shell covers 102 and 103 tosuction, discharge, or inject a refrigerant. The pipes 104, 105, and 106include a suction pipe 104, a discharge pipe 105, and a process pipe106.

The suction pipe 104 is provided to suction a refrigerant into thelinear compressor 10. For example, the suction pipe 104 may be coupledto the first shell cover 102. A refrigerant can be suctioned into thelinear compressor 10 axially through the suction pipe 104.

The discharge pipe 105 is provided to discharge a compressed refrigerantout of the linear compressor 10. The discharge pipe 105 may be coupledto the outer side of the shell 101. The refrigerant suctioned throughthe suction pipe 104 can be compressed while axially flowing. Thecompressed refrigerant can be discharged through the discharge pipe 105.The discharge pipe 105 may be positioned closer to the second shellcover 103 than the first shell cover 102.

The process pipe 106 is provided to replenish the linear compressor 10with a refrigerant. The process pipe 106 may be coupled to the outerside of the shell 101. A worker can inject a refrigerant into the linearcompressor 10 through the process pipe 106.

The processor pipe 106 may be coupled to the shell 101 at a differentheight from the discharge pipe 105 to avoid interference with thedischarge pipe 105. The height is understood as the vertical (or radial)distance from the legs 50. Since the discharge pipe 105 and the processpipe 105 are coupled at different heights to the outer side of the shell101, a worker can conveniently work.

At least a portion of the second shell cover 103 may be positioned onthe inner side of the shell 101, close to the position where the processpipe 106 is coupled. That is, at least a portion of the second shellcover 103 can act as resistance against the refrigerant that is injectedthrough the process pipe 106.

Accordingly, in terms of a channel for a refrigerant, a channel for arefrigerant that flows inside through the process pipe 106 is formedsuch that the size decreases toward the inside of the shell 101. In thisprocess, the pressure of the refrigerant is reduced, so the refrigerantmay vaporize.

Further, in this process, oil contained in the refrigerant may beremoved. Accordingly, a gas refrigerant with oil removed flows into apiston 130, so the performance of compressing a refrigerant can beimproved. The oil may be understood as a working oil existing in acooling system.

FIG. 2 is an exploded view showing the components in the linearcompressor according to an embodiment of the present invention and FIG.3 is a cross-sectional view taken along line A-A′ of FIG. 4. The shell101 and the shell covers 102 and 103 are not shown in FIG. 2 for theconvenience of description.

As shown in FIGS. 2 and 3, the linear compressor 10 according to anaspect of the present invention includes a frame 110, a cylinder 120, apiston 130, and a motor assembly 140. As shown in FIGS. 2 and 3, thelinear compressor 10 according to an aspect of the present inventionincludes a frame 110, a cylinder 120, a piston 130, and a motor assembly140. The motor assembly 140 is a linear motor that provides a drivingforce to the piston 130 and the piston 130 can be reciprocated byoperation of the motor assembly 140.

Directions are defined as follows.

The term “axial direction” may be understood as the reciprocationdirection of the piston 130, that is, the transverse direction in FIG.3. In the “axial direction”, the direction going toward the compressionspace P from the suction pipe 104, that is, the flow direction of arefrigerant is defined as a “forward direction” and the oppositedirection is defined as a “rear direction” When the piston 130 is movedforward, the compression space P can be compressed.

Meanwhile, the term “radial direction”, which is the directionperpendicular to the reciprocation direction of the piston 130, may beunderstood as the vertical direction in FIG. 3. In the “radialdirection”, the direction going toward the shell 101 from the centeraxis of the piston 130 is defined as a radial “outward direction” andthe opposite direction is defined as a radial “inward direction”.

The cylinder 120 is disposed inside the frame 110. The frame 110 isunderstood as a component for fixing the cylinder 120. For example, thecylinder 120 may be forcibly fitted in the frame 110.

The frame 110 includes a frame body 111 axially extending and a frameflange 112 extending radially outward from the frame body 111. The framebody 111 and the frame flange 112 may be integrated.

The frame body 111 is formed in a cylindrical shape with open axial topand bottom. The cylinder 120 is disposed radially inside the frame body111. The frame flange 112 is formed in a disc shape having apredetermined axial thickness. In particular, the frame flange 112radially extends from the front end of the frame body 111.

A gas hole 113 recessed rearward from the front surface of the frameflange 112 is formed on the frame flange 112. A gas channel 114extending through the frame flange 112 and the frame body 111 from thegas hole 113 is formed in the frame 110.

The piston 130 is movably disposed in the cylinder 120. The cylinder 120includes a cylinder body 121 axially extending and a cylinder flange 122formed on the outer side of the front portion of the cylinder body 121.

The cylinder body 121 is formed in a cylindrical shape having a centralaxis and is inserted in the frame body 111. Accordingly, the outer sideof the cylinder body 121 may be positioned to face the inner side of theframe body 111.

The cylinder flange 122 extends radially outward and extends forwardfrom the front portion of the cylinder body 121. When the cylinder 120is inserted into the frame 110, the cylinder flange 122 is deformed, sothe cylinder 120 can be forcibly fitted.

A gas inlet 126 is recessed radially inward on the outer side of thecylinder body 121. The gas inlet 126 may be circumferentially formedaround the outer side of the cylinder body 121 about the central axis. Aplurality of gas inlets 126 may be provided. For example, two gas inlets126 may be provided.

The cylinder body 121 includes a cylinder nozzle 125 extending radiallyinward from the gas inlet 126. The cylinder nozzle 125 may extend to theinner side of the cylinder body 121. That is, the cylinder nozzle 125extends to the outside around the piston 130.

By this structure, a refrigerant that function as a gas bearing can besupplied to the piston 130. In detail, at least some of a refrigerantflows inside through the gas hole 113. Further, the refrigerant issupplied to the outside around the cylinder 120 along the gas channel114. Further, the refrigerant can be supplied to the piston 130 throughthe gas inlet 126 and the cylinder nozzle 125.

The piston 130 includes a substantially cylindrical piston body 131 anda piston flange 132 radially extending from the piston body 131. Thepiston body 131 can reciprocate in the cylinder 120 and the pistonflange 132 can reciprocate outside the cylinder 120.

The linear compressor 10 further includes a suction muffler 150 disposedin the piston 130. The suction muffler 150 is a component for reducingnoise that is generated by a refrigerant suctioned through the suctionpipe 104. In detail, the refrigerant suctioned through the suction pipe104 flows into the piston 130 through the suction muffler 150. The flownoise of the refrigerant can be reduced while the refrigerant flowsthrough the suction muffler 150.

The suction muffler 150 includes a plurality of mufflers 151, 152, and153. The mufflers 151, 152, and 153 include a first muffler 151, asecond muffler 152, and a third muffler 153 that are assembled together.The refrigerant suctioned through the suction pipe 104 can sequentiallyflow through the third muffler 153, the second muffler 152, and thefirst muffler 151.

In detail, the first muffler 151 is disposed in the piston 130 and thesecond muffler 152 is coupled to the rear end of the first muffler 151.The third muffler 153 receives the second muffler 152 and may extendrearward from the first muffler 151.

As shown in FIGS. 2 and 3, the first muffler 151 may be formed such thatthe area increases in the flow direction of a refrigerant. That is, thefirst muffler 151 has a tapered portion in which a flow cross-sectionalarea gradually increases in the flow direction of a refrigerant.

By this structure, the cross-sectional area through which a refrigerantflows gradually increases, the flow speed of the refrigerant graduallydecreases, and the pressure of the refrigerant increases. Further, thepressure of the refrigerant can further increases, a suction valve 135to be described below can be more quickly bent, and a larger amount ofrefrigerant can flow to the compression space P.

The compression space P, which is a space where a refrigerant iscompressed by the piston 130, is defined in the cylinder 120 and aheadof the piston 130.

Suction holes 133 allowing a refrigerant to flow into the compressionspace P are formed at the front of the piston 130 and a suction valve135 for selectively opening the suction holes 133 is disposed ahead ofthe suction holes 133. The suction valve 135 can be coupled to thepiston 130 by a fastener 136.

A discharge cover 160 defining a discharge space 160 a for therefrigerant discharged from the compression space P and a dischargevalve assembly 161 and 163 coupled to the discharge cover 160 toselectively discharge the refrigerant compressed in the compressionspace P are disposed ahead of the compression space P. The dischargespace 160 a includes a plurality of sections divided by the inner sideof the discharge cover 160. The sections are arranged in the front-reardirection and can communicate with one another.

The discharge valve assembly 161 and 163 includes a discharge valve 161that allows a refrigerant to flow into the discharge space of thedischarge cover 160 by opening when the pressure in the compressionspace P becomes a discharge pressure or more and a spring assembly 163that is disposed between the discharge valve 161 and the discharge cover160 and axially provides elasticity.

The spring assembly 163 includes a valve spring 163 a and a springfixing assembly 163 b for supporting the valve spring 163 a on thedischarge cover 160. For example, the valve spring 163 a may include aplate spring. The spring fixing assembly 163 b may be integrally formedwith the valve spring 163 a by injection molding.

The discharge valve 161 is coupled to the valve spring 163 a and therear portion or the rear surface of the discharge valve 161 is disposedto be able to be supported on the front surface of the cylinder 120.When the discharge valve 161 is supported on the front surface of thecylinder 120, the compression space P is maintained in a sealed state,and when the discharge valve 161 is spaced from the front surface of thecylinder 120, the compression space P is opened and the compressedrefrigerant in the compression space P can be discharged.

The linear compressor 10 further includes a retainer 165 coupled to thedischarge cover 160 and supporting a side of the body of the compressor10. The retainer 165 is disposed close to the second shell 103 and canelastically support the body of the compressor 10.

In detail, the retainer 165 includes a supporting spring 166. A springholder 101 a may be disposed on the inner side of the shell 101, closeto the second shell cover 103. The supporting spring 166 may be coupledto the spring holder 101 a. Since the spring holder 101 a and theretainer 165 are coupled to each other, the body of the compressor canbe stably supported in the shell 101.

The compression space P can be understood as a space defined between thesuction valve 135 and the discharge valve 161. The suction valve 135 maybe formed at a side of the compression space P and the discharge valve161 may be disposed at the other side of the compression space P, thatis, opposite the suction valve 135.

When the pressure in the compression space P decreases to a suctionpressure or less and lower than a discharge pressure while the piston130 reciprocates in the cylinder 120, the suction valve 135 is openedand a refrigerant is suctioned into the compression space P. However,when the pressure in the compression space P increases to the suctionpressure or more, the refrigerant in the compression space P iscompressed with the suction valve 135 closed.

When the pressure in the compression space P increases to the dischargepressure or more, the valve spring 163 a opens the discharge valve 161by deforming forward and a refrigerant is discharged from thecompression space P into the discharge space 160 of the discharge cover160. When the refrigerant finishes being discharged, the valve spring163 a provides a restoring force to the discharge valve 161, so thedischarge valve 161 is closed.

The linear compressor 10 further includes a cover pipe 162 a coupled tothe discharge cover 160 to discharge the refrigerant flowing through thedischarge space 160 a of the discharge cover 160. For example, the coverpipe 162 a may be made of metal.

The linear compressor 10 further includes a loop pipe 162 b coupled tothe cover pipe 162 a to transmit the refrigerant flowing through thecover pipe 162 a to the discharge pipe 105. The loop pipe 612 b may becoupled to the cover pipe 162 a at a side and to the discharge pipe 105at the other side.

The loop pipe 162 b is made of a flexible material and may have arelatively large length. The loop pipe 162 b may be rounded along theinner side of the shell 101 from the cover pipe 162 a and coupled to thedischarge pipe 105. For example, the loop pipe 162 b may be wound.

The motor assembly 140 includes an outer stator 141 fixed to the frame110 around the cylinder 120, an inner stator 148 spaced apart inwardfrom the outer stator 141, and a permanent magnet 146 disposed in thespace between the outer stator 141 and the inner stator 148.

The permanent magnet 146 can be reciprocated straight by a mutualelectromagnetic force with the outer stator 141 and the inner stator148. The permanent magnet 146 may be a single magnet having one pole ormay be formed by combining a plurality of magnets having three poles.

The permanent magnet 146 may be disposed on a magnet frame 138. Themagnet frame 138 may have a substantially cylindrical shape and may beinserted in the space between the outer stator 141 and the inner stator148.

In detail, on the basis of the cross-sectional view of FIG. 3, themagnet frame 138 may extend radially outward from the rear side of thepiston 130 and may bend forward. The permanent magnet 146 may bedisposed at the rear portion of the magnet frame 138. When the permanentmagnet 146 reciprocates, the piston 130 can axially reciprocate with thepermanent magnet 146.

The outer stator 141 includes a coil assembly 141 b, 141 c, and 141 dand a stator core 141 a. The coil assembly 141 b, 141 c, and 141 dincludes a bobbin 141 b and a coil 141 c circumferentially wound aroundthe bobbin.

The coil assembly 141 b, 141 c, and 141 d further includes a terminal141 d leading or exposing a power line connected to the coil 141 c tothe outside of the outer stator 141. The terminal 141 d can be led orexposed to the outside through the front from the rear of the frame 110through the frame flange 112.

The stator core 141 a includes a plurality of core blocks formed bycircumferentially stacking a plurality of laminations. The core blocksmay be arranged around at least a portion of the coil assembly 141 b and141 c.

A stator cover 149 is disposed at a side of the outer stator 141. In theouter stator 141, a side may be supported by the frame 110 and the otherside may be supported by the stator cover 149.

The linear compressor 10 further includes cover fasteners 149 a forfastening the stator cover 149 and the frame 110. The cover fasteners149 a may extend forward toward the frame 110 through the stator cover149 and may be coupled to the frame 110.

The inner stator 148 is fixed to the outer side of the frame 110. Theinner stator 148 is formed by stacking a plurality of laminationscircumferentially outside the frame 110.

That is, the inner stator 148 is coupled to the radial outer side of theframe body 111. The inner stator 148 disposed on the radial outer sideof the frame body 111, the permanent magnet 146, and the outer stator141 are disposed axially behind the frame flange 112.

The configuration of the linear compressor 10 may include aconfiguration that reciprocates and a configuration that supports thereciprocating configuration. The linear compressor 10 according to anaspect of the present invention includes a spring 200 elasticallysupporting the reciprocating configuration. The spring 200 is describedin detail hereafter.

FIG. 4 is a view showing a coupling structure of the linear compressoraccording to an embodiment of the present invention.

As shown in FIG. 4, the linear compressor includes a driving assembly Dand a supporting assembly S. The supporting assembly may be referred toas a fixed assembly.

The driving assembly D can be understood as an assembly of componentsthat reciprocate in the compressor 10. Accordingly, the driving assemblyD includes the piston 130, the permanent magnet 146, the magnet frame138, and the suction muffler 150.

The supporting assembly S can be understood as a configuration that doesnot reciprocate in the compressor 10. Accordingly, the supportingassembly S can also be understood as a configuration that is not thedriving assembly D in the shell 101.

The supporting assembly S is a configuration that supports motions ofthe driving assembly D. In detail, the supporting assembly S supportsthe driving assembly D in the shell 101. Accordingly, the drivingassembly D can reciprocate at a predetermined distance from the shell101.

Referring to FIG. 4, the supporting assembly S includes the frame 110,the outer stator 141, the inner stator 148, and the stator cover 149.For the convenience of illustration, the discharge cover 160, etc. thatare coupled to the upper portion of the frame 110 are not shown.

The above description is referred to for the components of the drivingassembly D and the supporting assembly S and the combination of thecomponents. Further, the driving assembly D and the supporting assemblyS are discriminated on the basis of the above description and they maybe discriminated in different ways when other configurations are addedto or removed from the linear compressor 10.

The spring 200 can be understood as a resonant spring for stablereciprocation of the driving assembly D. In particular, the spring 200can reduce vibration or noise due to movement of the driving assembly D.

Accordingly, the spring 200 can be axially stretched and compressed. Inother words, the spring 200 can reduce vibration or noise due tomovement of the driving assembly D, using tensile force or compressiveforce. For example, the spring 200 may have the shape of a coil springthat is axially stretched or compressed.

Referring to FIG. 3, the spring 200 is disposed close to the first shellcover 102. In particular, the spring 200 may be disposed behind thepiston 130. That is, the spring 200 can be understood as a structurethat supports the driving assembly D axially behind it. A separateretainer may be further provided between the spring 200 and the firstshell cover 102.

The spring 200 connects the driving assembly D and the supportingassembly S. That is, the spring 200 can be combined with the drivingassembly D and the supporting assembly S.

Different combination lines are provided to discriminate thecombinations of the configurations in FIG. 4. In detail, the combinationline of the spring 200 and the supporting assembly S is shown as adot-dashed line. In detail, the combination line of the spring 200 andthe supporting assembly S is shown as a double-dot-dashed line.

In particular, an end of the spring 200 can be fixed with the drivingassembly D and the other end of the spring 200 can be fixed with thesupporting assembly S. Accordingly, the spring 200 is disposed with bothends fixed. Therefore, in the linear compressor 10 according to anaspect of the present invention, both of tensile force and compressiveforce of the spring 200 can be used.

Referring to FIG. 4, an end of the spring 200 is fixed to the statorcover 149 and the other end of the spring 200 is fixed to the suctionmuffler 150. For example, the spring 200 can be fixed to the statorcover 149 and the suction muffler 150 by welding.

However, this coupling is just an example. In short, the spring 200 canconnect at least one component of the driving assembly D and at leastone component of the supporting assembly S. In particular, any one ofboth ends of the spring 200 is fixed to the driving assembly D and theother one is fixed to the supporting assembly S.

The operation of the compressor 10 according to this coupling structureis briefly described. When the compressor 10 is operated, the drivingassembly D reciprocates. Accordingly, the end of the spring 200 fixed tothe driving assembly D also reciprocates. The end of the spring 200fixed to the supporting assembly S is fixed at a predetermined positionin this process.

Accordingly, when the driving assembly D moves forward, both ends of thespring 200 move away from each other, whereby the spring 200 isstretched. On the other hand, when the driving assembly D movesrearward, both ends of the spring 200 move close to each other, wherebythe spring 200 is compressed. As the spring 200 is stretched orcompressed, as described above, the driving assembly D can beelastically supported.

As shown in FIG. 4, the spring 200 is a coil spring that is axiallystretched and compressed. In detail, the spring 200 axially spirallyextends. Accordingly, the spring 200 can form a virtual circle having aspring diameter R (see FIG. 6) in the radial direction.

The center of the spring diameter R is referred to as a spring centerand a line axially extending from the spring center is referred to as aspring central axis C. The central axis of the linear compressor 10according to an aspect of the present invention and the spring centralaxis C coincide.

The central axis of the compressor 10 can be understood as the centralaxis of the configuration of the compressor 10. For example, the centralaxis may be central axes of the cylindrical shell 101, the frame body111, the cylinder body 121, and the piston body 131. Eccentricity due tooperation and design errors are not considered in this case.

In particular, the spring central axis C coincides with thereciprocation central axis of the driving assembly D. Accordingly, forceexcept for axial tensile or compressive force can be minimized when thespring 200 supports the driving assembly D. That is, lateral force canbe minimized, so the spring 200 can effectively support the drivingassembly D.

The suction muffler 150 is disposed inside the spring 200. In detail,the spring 200 axially extends around the suction muffler 150. Inparticular, the spring 200 spirally extends radially outside the thirdmuffler 153.

Accordingly, the spring diameter R is larger than the diameter of thesuction muffler 150. Further, the spring diameter R may be larger thanthe diameter of the piston flange 132 or the magnet frame 138. That is,the spring 200 has a relatively large diameter.

Accordingly, rigidity of the spring 200 is increased and the spring 200can resist better repetitive load due to reciprocation. As thesupporting force of the spring 200 is increased, the driving assemblycan be operated at a high speed.

Further, since the spring 200 is disposed around the suction muffler150, the internal space of the compressor 10 can be effectively used. Inparticular, the rear cover, etc. of the linear compressors of therelated art can be removed, so the axial length of the compressor 10 canbe reduced.

The spring 200 can be divided into a spring body 202 and end portions ofthe spring body 202.

In detail, the spring body 202 axially extends while radially forming acircle having the spring diameter R. Accordingly, the spring body 202can be formed in a spiral shape axially extending. In other words, thespring body 202 extends with a curvature that radially forms the springdiameter R.

Both end portions of the spring body 202 extend with a radiallydifferent curvature from the spring diameter R. Accordingly, both endsof the spring body 202 are positioned radially outside or inside thespring body 202.

For the convenience of description, the end positioned axially ahead ofthe spring body 202 is referred to as a front spring link 204 and theend positioned axially behind the spring body 202 is referred to as arear spring link 206. Accordingly, in FIG. 4, the portion positioned atthe left side is the front spring link 204 and the portion positioned atthe right side is the rear spring link 206.

Further, as indicated by combination lines in FIG. 4, the front springlink 204 is coupled to the supporting assembly S and the rear springlink 206 is coupled to the driving assembly D. In particular, the frontspring link 204 is coupled to the rear surface of the stator cover 149and the rear spring link 206 is coupled to the rear end of the thirdmuffler 153.

However, this is just an example, and any one of both end portions ofthe spring 200 may be coupled to the supporting assembly S and the otherone may be coupled to the driving assembly D.

The coupling structure of the spring 200 is described in detailhereafter.

FIGS. 5 and 6 are views showing a spring of a linear compressoraccording to a first embodiment of the present invention.

As shown in FIGS. 5 and 6, the spring 200 includes a first bracket 240coupled to the front spring link 204 and a second bracket 260 coupled tothe rear spring link 206. The first bracket 240 and the second bracket260 are understood as components that fix the spring 200 to the drivingassembly D or the supporting assembly S.

The first bracket 240 may be a flat plate radially extending.Accordingly, the first bracket 240 can form one plane perpendicular tothe axial direction. The first bracket 240 may have a portion thatprotrudes axially rearward to fix the front spring link 204.

For example, the first bracket 240 can be coupled to the stator cover149. Accordingly, the first bracket 240 may be a ring-shaped flat platecorresponding to the stator cover 149. An opening for avoiding the coverfasteners 149 a coupled to the stator cover 149 may be formed at thefirst bracket 240.

The second bracket 260 may be formed in a flat plate shape radiallyextending with the edge axially bending. The second bracket 260 formsone plane perpendicular to the axial direction. In particular, thesecond bracket 260 bends axially rearward around at least a portion ofthe rear spring link 206.

For example, the second bracket 260 can be coupled to the suctionmuffler 150. In detail, the second bracket 260 can be coupled to therear surface of the third muffler 153 into which a refrigerant flows.Accordingly, a hole for flow of a refrigerant may be formed at thesecond bracket 260.

The spring 200 is composed of a plurality of spring strands. Inparticular, the spring 200 according to the linear compressor accordingto an aspect of the present invention may be composed of three springstrands 210, 220, and 230.

The term ‘spring strands’ is used for the convenience of description,but the spring strands 210, 220, and 230 are not a part of a spring, butcomplete products. In other words, the spring 200 of the presentinvention can be understood as being formed by combining a plurality ofsprings.

The spring strands 210, 220, and 230 are the same. In detail, the springstrands 210, 220, and 230 may be the same in shape and size. That is,the spring strands may be made of the same material through the samemanufacturing process.

For the convenience of description, the spring strands are respectivelyreferred to as a first spring strand 210, a second spring strand 220,and a third spring strand 230.

The first, second, and third spring strands 210, 220, and 230 arecircumferentially differently turned. The term ‘circumferential’ meansany one of ‘clockwise’ and ‘counterclockwise’. The first, second, andthird spring strands 210, 220, and 230 are circumferentially turned atthe same angle. That is, the spring strands 210, 220, and 230 are turnedat 120 degrees with respect to one another.

For example, assuming that the first spring strand 210 is the center (0degrees or 360 degrees), the second spring strand 220 is positionedcircumferentially at 120 degrees from the first spring strand 210.Further, the third spring strand 230 is positioned at 240 degrees fromthe first spring strand 210 and at 120 degrees from the second springstrand 220.

The spring strands 210, 220, and 230 are each divided into a spring bodyand both ends (a front spring link and a rear spring link). The lengthsof the spring bodies, the lengths of both ends, and bending angles ofthe spring strands 210, 220, and 230 are the same.

In detail, the first spring strand 210 is divided into a first springbody 212, a first front spring link 214, and a first rear spring link216. The second spring strand 220 is divided into a second spring body222, a second front spring link 224, and a second rear spring link 226.The third spring strand 230 is divided into a third spring body 232, athird front spring link 234, and a third rear spring link 236.

The first, second, and third spring bodies 212, 222, and 232 extend withthe same spring diameter R. Accordingly, the entire shape of the springbody 202 can be a cylindrical shape. In detail, a cylindrical shapeaxially extending and having the spring diameter R radially from thespring central axis C is formed.

The first, second, and third front spring links 214, 224, and 234 bendradially outward. In other words, the first, second, and third frontspring links 214, 224, and 234 are disposed radially outside the springbody 202.

The first bracket 240 is coupled to the first, second, and third frontspring links 214, 224, and 234. That is, the first bracket 240 can beunderstood as a component that fixes the front spring links 214, 224,and 234 axially in the same plane.

As described above, the first bracket 240 may be formed in a ring shape.Accordingly, the first bracket 240 has an outer diameter and an innerdiameter with respect to the central axis C.

The outer diameter of the first bracket 240 is larger than the springdiameter R. For example, the outer diameter of the first bracket 240 maycorrespond to a virtual circle constructed by circumferentiallyextending the radial outermost ends of the first, second, and thirdfront spring links 214, 224, and 234.

The inner diameter of the first bracket 240 is smaller than the springdiameter R. Accordingly, when the spring 200 is compressed, the firstbracket 240 can support at least a portion of the spring body 202.

The first, second, and third rear spring links 216, 226, and 236 bendradially inward. In other words, the first, second, and third rearspring links 216, 226, and 236 are disposed radially inside the springbody 202. The first, second, and third rear spring links 216, 226, and236 can be understood as extending toward the central axis C.

The second bracket 260 is coupled to the first, second, and third rearspring links 216, 226, and 236. That is, the second bracket 260 can beunderstood as a component that fixes the rear spring links 216, 226, and236 axially in the same plane.

The second bracket 260 radially protrudes at 120 degrees around thecentral axis C. The second bracket 260 radially protrudes from thecentral axis to fix the first, second, and third rear spring links 216,226, and 236 circumferentially spaced apart from one another at 120degrees.

The bending angles or lengths of the first, second, and third frontspring links 214, 224, and 234 and the first, second, and third rearspring links 216, 226, and 236 may be different, depending on design. Inparticular, the bending angles or lengths may be different, depending onthe coupling structures of the first, second, and third front springlinks 214, 224, and 234 and the first, second, and third rear springlinks 216, 226, and 236.

As described above, the spring of the present invention may include aplurality of spring strands and a pair of brackets connecting the springstrands. The spring strands and the pair of brackets may be changed invarious shapes. Exemplary shapes of the spring strands and the pair ofbrackets are described hereafter. The above description is referred tofor the same configuration and the same components are indicated bydifferent reference numerals for the convenience of understanding.

FIGS. 7 and 8 are views showing a spring of a linear compressoraccording to a second embodiment of the present invention.

As shown in FIGS. 7 and 8, a spring 300 includes a first bracket 340coupled to a front spring link 304 and a second bracket 360 coupled to arear spring link 306.

The first bracket 340 may be a flat plate radially extending.Accordingly, the first bracket 340 can form one plane perpendicular tothe axial direction. The first bracket 340 may have a portion thatprotrudes axially rearward to fix the front spring link 204.

The first bracket 340 may be the stator cover 149. That is, the statorcover 149 itself can function as the first bracket 340. Accordingly, thefirst bracket 340 supports a side of the outer stator 131 and is coupledto the frame 110 by the cover fasteners 149 a.

In other words, the first bracket 340 can be understood as not beingprovided. Accordingly, the front spring link 306 can be understood asbeing directly coupled to the stator cover 149. In FIGS. 7 and 8, bothreference numerals are shown to show that the first bracket 340 and thestator cover 149 are the same component.

The second bracket 360 may be a flat plate radially extending.Accordingly, the second bracket 360 can form one plane perpendicular tothe axial direction. The second bracket 360 may have a portion thatprotrudes axially forward to fix the rear spring link 206.

For example, the second bracket 360 can be coupled to the suctionmuffler 150. In detail, the second bracket 260 can be coupled to therear surface of the third muffler 153 into which a refrigerant flows.Accordingly, a hole for flow of a refrigerant may be formed at thesecond bracket 360.

The spring 300 is composed of a plurality of spring strands 310, 320,and 330. The spring 300 is divided into a spring body 302 spirallyextending and both ends (hereafter, a front spring link 304 and a rearspring link 306) of the spring body 302.

The spring strands have the same shape and are circumferentially spacedapart from one another with the same intervals. The spring strandsinclude a first spring strand 310, a second spring strand 320, and athird spring strand 330.

The first, second, and third spring strands 310, 320, and 330 arecircumferentially differently turned. The term ‘circumferential’ meansany one of ‘clockwise’ and ‘counterclockwise’. The first, second, andthird spring strands 310, 320, and 330 are circumferentially turned atthe same angle. That is, the spring strands 310, 320, and 330 are turnedat 120 degrees with respect to one another.

The spring strands 310, 320, and 330 are each divided into a spring bodyand both ends (a front spring link and a rear spring link). In detail,the first spring strand 310 is divided into a first spring body 312, afirst front spring link 314, and a first rear spring link 316. Thesecond spring strand 320 is divided into a second spring body 322, asecond front spring link 324, and a second rear spring link 326. Thethird spring strand 330 is divided into a third spring body 332, a thirdfront spring link 334, and a third rear spring link 336.

The first, second, and third spring bodies 310, 320, and 330 extendwhile each forming a virtual circle having a spring diameter R in theradial direction. The center of the spring diameter R is referred to asa spring center and a line axially extending from the spring center isreferred to as a spring central axis C. The spring central axis Ccoincides with a reciprocation central axis of the driving assemblyincluding the piston 130.

The first, second, and third spring bodies 310, 320, and 330 extend suchthat the spring diameter R is radially changed. Referring to FIG. 8, thespring body 302 close to the front spring link 304 has a first springdiameter R1 and the spring body 302 close to the rear spring link 306has a second spring diameter R2.

The second spring diameter R2 is smaller than the first spring diameterR1. That is, the spring body 302 extends such that the spring diameterdecreases from the axial front portion to rear portion.

Accordingly, the entire shape of the spring body 302 can be a circularconical shape. In detail, it is a frustoconical shape. Accordingly, anend of the spring body 302 has the first spring diameter R1 in theradial direction and the other end of the spring body 302 has the secondspring diameter R2 in the radial direction with respect to the springcentral axis C. Further, the spring body 302 axially extends by a springheight H.

The first spring diameter R1 and the second spring diameter R2 arecoaxially defined. That is, the centers of the first spring diameter R1and the second spring diameter R2 are the same and a line axiallyextending from the centers is the spring central axis C.

The first, second, and third front spring links 314, 324, and 334 bendradially outward. In other words, the first, second, and third frontspring links 314, 324, and 334 are disposed radially outside the springbody 302.

The first bracket 340 is coupled to the first, second, and third frontspring links 314, 324, and 334. That is, the first bracket 340 can beunderstood as a component that fixes the front spring links 314, 324,and 334 axially in the same plane.

Further, as described above, the first bracket 340 is the stator cover149. Accordingly, the first bracket 340 is formed in a ring shape havingan outer diameter and an inner diameter with respect to the central axisC and the edge of the first bracket 340 may extend axially rearward.

The outer diameter of the first bracket 340 is larger than the springdiameter R and smaller than the inner diameter of the shell 101.Accordingly, the radial outermost ends of the first, second, and thirdfront spring links 314, 324, and 334 can be seated inside the firstbracket 240.

The inner diameter of the first bracket 340 is smaller than the springdiameter R. Accordingly, when the spring 300 is compressed, the firstbracket 340 can support at least a portion of the spring body 302.

The first, second, and third rear spring links 316, 326, and 336 bendradially inward. In other words, the first, second, and third rearspring links 316, 326, and 336 are disposed radially inside the springbody 302. The first, second, and third rear spring links 316, 326, and336 can be understood as extending toward the central axis C.

The second bracket 360 is coupled to the first, second, and third rearspring links 316, 326, and 336. That is, the second bracket 360 can beunderstood as a component that fixes the rear spring links 316, 326, and336 axially in the same plane. The second bracket 360 may be a circularflat plate radially extending from the central axis C.

As described above, the spring of the present invention may havedifferent spring diameters R in the radial direction and may havevarious shapes of brackets.

FIG. 9 is a view showing a coupling structure of a linear compressoraccording to another embodiment of the present invention.

As shown in FIG. 9, the linear compressor includes a spring 400, adriving assembly D, and a supporting assembly S. The driving assembly Dand the supporting assembly S shown in FIG. 9 are the same as thoseshown in FIG. 4. Accordingly, they are not described and the descriptionreferring to FIG. 4 is substituted.

The spring 400 connects the driving assembly D and the supportingassembly S. That is, the spring 400 can be combined with the drivingassembly D and the supporting assembly S.

Different combination lines are provided to discriminate thecombinations of the configurations in FIG. 9. In detail, the combinationline of the spring 400 and the supporting assembly S is shown as adot-dashed line. In detail, the combination line of the spring 200 andthe supporting assembly S is shown as a double-dot-dashed line.

In particular, an end of the spring 400 can be fixed with the drivingassembly D and the other end of the spring 400 can be fixed with thesupporting assembly S. Accordingly, the spring 400 is disposed with bothends fixed. Therefore, in the linear compressor 10 according to anaspect of the present invention, both of tensile force and compressiveforce of the spring 400 can be used.

Referring to FIG. 9, an end of the spring 400 is fixed to the statorcover 149 by predetermined spring fasteners 450. The other end of thespring 400 is fixed to the magnet frame 138. For example, the spring 400can be directly or indirectly fixed to the stator cover 149 and themagnet frame 138 by welding.

However, this coupling is just an example. In short, the spring 400 canconnect at least one component of the driving assembly D and at leastone component of the supporting assembly S. In particular, any one ofboth ends of the spring 400 is fixed to the driving assembly D and theother one is fixed to the supporting assembly S.

As shown in FIG. 9, the spring 400 is a coil spring that is axiallystretched and compressed. In detail, the spring 400 axially spirallyextends. The spring 400 spirally extends around the spring central axisC.

The central axis of the linear compressor 10 according to an aspect ofthe present invention and the spring central axis C coincide. Inparticular, the spring central axis C coincides with the reciprocationcentral axis of the driving assembly D.

The suction muffler 150 is disposed inside the spring 400. In detail,the spring 400 axially extends around the suction muffler 150. Inparticular, the spring 400 spirally extends radially outside the thirdmuffler 153.

The spring 400 can be divided into a spring body 402 and end portions ofthe spring body 402. For the convenience of description, the endpositioned axially ahead of the spring body 402 is referred to as afront spring link 404 and the end positioned axially behind the springbody 402 is referred to as a rear spring link 406.

Further, as indicated by combination lines in FIG. 9, the front springlink 404 is coupled to the driving assembly D and the rear spring link406 is coupled to the supporting assembly S. In particular, the frontspring link 404 is coupled to the rear end of the magnet frame 130 andthe rear spring link 406 is coupled to the rear end of the stator cover149.

Further, it can be seen that the spring body 402 is positioned axiallybehind the magnet frame 138 and the stator cover 149. The spring body402 may have a diameter larger than the magnet frame 138. That is, thespring body 402 may be disposed radially outside the magnet frame 138.

That is, as compared with the spring 200 shown in FIG. 4, the frontspring link 404 and the rear spring link 406 may be coupled to thedriving assembly D and the supporting assembly S while crossing eachother.

The coupling structure of the spring 400 shown in FIG. 9 is described indetail hereafter.

FIGS. 10 and 11 are views showing a spring of a linear compressoraccording to a third embodiment of the present invention. Referring toFIGS. 10 and 11, a linear compressor according to the third embodimentis shown in a front perspective view and a rear perspective view, unlikeother embodiments, to effectively show the configuration of a spring.

As shown in FIGS. 10 and 11, the spring 400 includes a first bracket 440coupled to the front spring link 404 and a second bracket 460 coupled tothe rear spring link 406. The first bracket 440 and the second bracket460 are understood as components that fix the spring 400 to the drivingassembly D or the supporting assembly S.

The first bracket 440 may be a flat plate radially extending.Accordingly, the first bracket 440 can form one plane perpendicular tothe axial direction. The first bracket 440 may have a portion thatprotrudes axially rearward to fix the front spring link 404.

For example, the first bracket 440 can be coupled to the magnet frame138. In particular, the first bracket 440 can be coupled to a portionwhere the magnet frame 138 extends radially outward from the rearportion of the piston 130. That is, the first bracket 140 can be coupledto the rear end of the magnet frame 138.

Accordingly, the first bracket 440 may be a ring-shaped flat platecorresponding to the rear end of the magnet frame 138. An opening foravoiding the third muffler 153 coupled to center portion of the rear endof the magnet frame 138 may be formed at the first bracket 340.

The second bracket 460 may be a flat plate radially extending.Accordingly, the second bracket 460 can form one plane perpendicular tothe axial direction. The second bracket 460 may have a portion thatprotrudes axially forward to fix the rear spring link 406.

For example, the second bracket 460 can be coupled to the stator cover149. The spring fasteners 450 are coupled between the second bracket 460and the stator cover 149. That is, the second bracket 460 is indirectlycoupled to the stator cover 149.

A plurality of spring fasteners 450 axially extending may be provided.Referring to FIG. 9, three spring fasteners 450 are provided and arecircumferentially spaced apart from one another at 120 degrees.Accordingly, the second bracket 460 can be coupled and supported to thestator cover 149 at three points.

The spring 400 is composed of a plurality of spring strands 410, 420,and 430. The spring 400 is divided into a spring body 402 spirallyextending and both ends (hereafter, a front spring link 404 and a rearspring link 406) of the spring body 402.

The spring strands have the same shape and are circumferentially spacedapart from one another with the same intervals. The spring strandsinclude a first spring strand 410, a second spring strand 420, and athird spring strand 430.

The first, second, and third spring strands 410, 420, and 430 arecircumferentially differently turned. The term ‘circumferential’ meansany one of ‘clockwise’ and ‘counterclockwise’. The first, second, andthird spring strands 410, 420, and 430 are circumferentially turned atthe same angle. That is, the spring strands 410, 420, and 430 are turnedat 120 degrees with respect to one another.

The spring strands 410, 420, and 430 are each divided into a spring bodyand both ends (a front spring link and a rear spring link). In detail,the first spring strand 410 is divided into a first spring body 412, afirst front spring link 414, and a first rear spring link 416. Thesecond spring strand 420 is divided into a second spring body 422, asecond front spring link 424, and a second rear spring link 426. Thethird spring strand 430 is divided into a third spring body 432, a thirdfront spring link 434, and a third rear spring link 436.

The first, second, and third spring bodies 410, 420, and 430 extendwhile each forming a virtual circle having a spring diameter R in theradial direction. The center of the spring diameter R is referred to asa spring center and a line axially extending from the spring center isreferred to as a spring central axis C. The spring central axis Ccoincides with a reciprocation central axis of the driving assembly Dincluding the piston 130.

The first, second, and third spring bodies 410, 420, and 430 axiallyextend with the same spring diameter R. Accordingly, the entire shape ofthe spring body 402 can be a cylindrical shape.

The first, second, and third front spring links 414, 424, and 434 bendradially inward. In other words, the first, second, and third frontspring links 414, 424, and 434 are disposed radially inside the springbody 402. The first, second, and third front spring links 414, 424, and434 can be understood as extending toward the central axis C.

The first bracket 440 is coupled to the first, second, and third frontspring links 414, 424, and 434. That is, the first bracket 440 can beunderstood as a component that fixes the front spring links 414, 424,and 434 axially in the same plane.

As described above, the first bracket 440 may be formed in a ring shape.Accordingly, the first bracket 440 has an outer diameter and an innerdiameter with respect to the central axis C. The outer diameter of thefirst bracket 440 may correspond to the outer diameter of the magnetframe 138 and the inner diameter of the first bracket 440 may correspondto the outer diameter of the third muffler 153.

The first, second, and third rear spring links 416, 426, and 436 bendradially inward. In other words, the first, second, and third rearspring links 416, 426, and 436 are disposed radially inside the springbody 402. The first, second, and third rear spring links 416, 426, and436 can be understood as extending toward the central axis C.

The second bracket 460 is coupled to the first, second, and third rearspring links 416, 426, and 436. That is, the second bracket 460 can beunderstood as a component that fixes the rear spring links 416, 426, and436 axially in the same plane.

As described above, the second bracket 460 may be formed a flat plateshape radially extending from the central axis C. The outermost side ofthe second bracket 460 may be positioned axially in the same line as thestator cover 149. Accordingly, the stator cover 149 and the secondbracket 460 can be combined through the spring fasteners 450.

As described above, both ends of the spring of the present invention canbe bent radially inward and a pair of brackets can be disposed insidethe spring body.

FIGS. 12 and 13 are views showing a spring of a linear compressoraccording to a fourth embodiment of the present invention.

As shown in FIGS. 12 and 13, a spring 500 includes a first bracket 540coupled to a front spring link 504 and a second bracket 560 coupled to arear spring link 506.

The first bracket 540 may be a flat plate radially extending.Accordingly, the first bracket 540 can form one plane perpendicular tothe axial direction. The first bracket 540 may have a portion thatprotrudes axially rearward to fix the front spring link 504.

For example, the first bracket 540 can be coupled to the stator cover149. Accordingly, the first bracket 540 may be a ring-shaped flat platecorresponding to the stator cover 149. An opening for avoiding the coverfasteners 149 a coupled to the stator cover 149 may be formed at thefirst bracket 540.

The second bracket 560 may be formed in a shape with a plurality of rodsradially extending from the central axis C. Accordingly, the secondbracket 560 can form one plane perpendicular to the axial direction. Thesecond bracket 560 may have a portion for fixing the rear spring link506 at a radial end.

For example, the second bracket 560 can be coupled to the suctionmuffler 150. In detail, the second bracket 560 can be coupled to therear surface of the third muffler 153 into which a refrigerant flows.Accordingly, a hole for flow of a refrigerant may be formed at thesecond bracket 560.

The spring 500 is composed of a plurality of spring strands 510, 520,and 530. The spring 500 is divided into a spring body 502 spirallyextending and both ends (hereafter, a front spring link 504 and a rearspring link 506) of the spring body 502.

The spring strands have the same shape and are circumferentially spacedapart from one another with the same intervals. The spring strandsinclude a first spring strand 510, a second spring strand 520, and athird spring strand 530.

The first, second, and third spring strands 510, 520, and 530 arecircumferentially differently turned. The term ‘circumferential’ meansany one of ‘clockwise’ and ‘counterclockwise’. The first, second, andthird spring strands 510, 520, and 530 are circumferentially turned atthe same angle. That is, the spring strands 510, 520, and 530 are turnedat 120 degrees with respect to one another.

The spring strands 510, 520, and 530 are each divided into a spring bodyand both ends (a front spring link and a rear spring link). In detail,the first spring strand 510 is divided into a first spring body 512, afirst front spring link 514, and a first rear spring link 516. Thesecond spring strand 520 is divided into a second spring body 522, asecond front spring link 524, and a second rear spring link 526. Thethird spring strand 530 is divided into a third spring body 532, a thirdfront spring link 534, and a third rear spring link 536.

The first, second, and third spring bodies 510, 520, and 530 extendwhile each forming a virtual circle having a spring diameter R in theradial direction. The center of the spring diameter R is referred to asa spring center and a line axially extending from the spring center isreferred to as a spring central axis C. The spring central axis Ccoincides with a reciprocation central axis of the driving assembly Dincluding the piston 130.

The first, second, and third spring bodies 510, 520, and 530 axiallyextend with the same spring diameter R. Accordingly, the entire shape ofthe spring body 502 can be a cylindrical shape.

The first, second, and third front spring links 514, 524, and 534 andthe first, second, and third rear spring links 516, 526, and 536 extendwith the same curvature as that of the spring body 502. Accordingly, thefirst, second, and third rear spring links 516, 526, and 536 arearranged radially in parallel with the spring body 502 and the first,second, and third front spring links 514, 524, and 534.

In other words, a bending end is not formed at the spring 500.Accordingly, the front spring link 504 and the rear spring link 506 canbe understood as a portion of the spring body 502.

The first bracket 540 is coupled to the first, second, and third frontspring links 514, 524, and 534. That is, the first bracket 340 can beunderstood as a component that fixes the front spring links 514, 524,and 534 axially in the same plane.

As described above, the first bracket 540 may be formed in a ring shape.Accordingly, the first bracket 540 has an outer diameter and an innerdiameter with respect to the central axis C.

The outer diameter of the first bracket 540 is larger than the springdiameter R. The inner diameter of the first bracket 540 is smaller thanthe spring diameter R. Accordingly, when the spring 500 is compressed,the first bracket 540 can support at least a portion of the spring body502.

The second bracket 560 is coupled to the first, second, and third rearspring links 516, 526, and 536. That is, the second bracket 560 can beunderstood as a component that fixes the rear spring links 516, 526, and536 axially in the same plane.

As described above, the second bracket 560 has a plurality of rodsradially extending from the central axis C. Accordingly, the secondbracket 560 may have three rods coupled to the first, second, and thirdrear spring links 516, 526, and 536. The rods are circumferentiallyspaced apart from each other at 120 degrees.

As described above, the spring of the present invention can be composedof spring strands having various shapes and brackets. The shapes shownin the figures are example and the spring of the present invention canbe modified in various ways.

What is claimed is:
 1. A linear compressor comprising: a shell thatdefines an accommodation space, the shell having an input sideconfigured to receive refrigerant and an output side configured todischarge refrigerant, the input side and the output side being spacedapart from each other in an axial direction of the linear compressor; acylinder that is disposed in the accommodation space and that defines acompression space configured to receive refrigerant in the accommodationspace; a piston located in the cylinder and configured to reciprocaterelative to the cylinder along the axial direction, the piston beingconfigured to compress refrigerant received in the cylinder; and aspring module configured to support the piston in the axial direction,the spring module comprising: a first bracket disposed at a first planeorthogonal to the axial direction, a second bracket disposed at a secondplane orthogonal to the axial direction and spaced apart from the firstbracket in the axial direction, and one or more spring strands thatdefine a spiral shape and that extend from the first bracket to thesecond bracket, each spring strand having a first end coupled to thefirst bracket and a second end coupled to the second bracket, whereinthe one or more spring strands define an inner circumference of thespring module and an outer circumference of the spring module, whereinthe first bracket extends radially outward of the outer circumference ofthe spring module, and wherein the second bracket is disposed radiallyinside of the inner circumference of the spring module.
 2. The linearcompressor of claim 1, wherein the spring module is disposed at an endof the cylinder facing the input side of the shell.
 3. The linearcompressor of claim 1, further comprising: a stator that is coupled tothe cylinder and that surrounds an outer circumferential surface of thecylinder, the stator comprising a stator cover located at an end of thestator and spaced apart from the outer circumferential surface of thecylinder.
 4. The linear compressor of claim 3, further comprising: asuction muffler that is located radially inward of the stator cover,that is coupled to the piston, and that is configured to supplyrefrigerant to the compression space.
 5. The linear compressor of claim4, wherein the first bracket is coupled to the stator cover, and thesecond bracket is coupled to the suction muffler.
 6. The linearcompressor of claim 4, wherein the one or more spring strands surroundan outer surface of the suction muffler.
 7. The linear compressor ofclaim 4, wherein the piston defines an inner space that extends alongthe axial direction and that accommodates a portion of the suctionmuffler.
 8. The linear compressor of claim 7, wherein the suctionmuffler comprises: a first suction muffler inserted to the inner spaceof the piston; and a second suction muffler coupled to the first suctionmuffler and disposed at an outside of the piston facing the input sideof the shell, and wherein the one or more spring strands surround anouter surface of the second suction muffler.
 9. The linear compressor ofclaim 1, wherein the first end is coupled to an outer portion of thefirst bracket that is outside of the outer circumference of the springmodule.
 10. The linear compressor of claim 1, wherein the second endextends radially inward from the inner circumference of the springmodule toward a spring central axis that extends in the axial direction.11. The linear compressor of claim 1, wherein the first bracket has aplanar shape, and wherein the second bracket comprises one or moreprotrusions that extend radially outward from a spring central axis,each protrusion of the second bracket defining a coupling spaceconfigured to receive the second end of one of the one or more springstrands.
 12. The linear compressor of claim 1, wherein each of the firstbracket and the second bracket has a circular plate shape, and wherein adiameter of the first bracket is greater than a diameter of the secondbracket.
 13. A linear compressor comprising: a shell that defines anaccommodation space, the shell having an input side configured toreceive refrigerant and an output side configured to dischargerefrigerant, the input side and the output side being spaced apart fromeach other in an axial direction of the linear compressor; a cylinderthat is disposed in the accommodation space and that defines acompression space configured to receive refrigerant in the accommodationspace; a piston located in the cylinder and configured to reciprocaterelative to the cylinder along the axial direction, the piston beingconfigured to compress refrigerant received in the cylinder; and aspring module that is disposed at an end of the cylinder facing theinput side of the shell and that is configured to support the piston inthe axial direction, the spring module comprising: a first bracketdisposed at a first plane orthogonal to the axial direction, a secondbracket disposed at a second plane orthogonal to the axial direction andspaced apart from the first bracket in the axial direction, and aplurality of spring strands coupled to the first bracket and the secondbracket, the plurality of spring strands defining a spiral shape woundabout a spring central axis that extends in the axial direction, whereineach of the plurality of spring strands extends from the first bracketto the second bracket and has a first end coupled to the first bracketand a second end coupled to the second bracket, wherein the plurality ofspring strands define an inner circumference of the spring module and anouter circumference of the spring module, wherein each first end of theplurality of spring strands is disposed radially outward of the outercircumference of the spring module, and wherein each second end of theplurality of spring strands is disposed radially inside of the innercircumference of the spring module.
 14. The linear compressor of claim13, wherein each first end of the plurality of spring strands isarranged about the spring central axis and spaced apart from other firstends in a circumferential direction of the spring module.
 15. The linearcompressor of claim 13, wherein each first end of the plurality ofspring strands is disposed radially outward of each second end of theplurality of spring strands.
 16. The linear compressor of claim 13,further comprising: a stator that is coupled to the cylinder and thatsurrounds an outer circumferential surface of the cylinder, the statorcomprising a stator cover located at an end of the stator and spacedapart from the outer circumferential surface of the cylinder; and asuction muffler that is located radially inward of the stator cover,that is coupled to the piston, and that is configured to supplyrefrigerant to the compression space.
 17. The linear compressor of claim16, wherein the first bracket is coupled to the stator cover, and thesecond bracket is coupled to the suction muffler.